Age-related neurocytotropism of mouse cytomegalovirus in explanted trigeminal ganglions

Abstract

Human cytomegalovirus (CMV) causes severe congenital neurologic disease; adult neural infection is associated with transient cranial nerve palsies. In our experimental model, mouse CMV (MCMV) infects neurons and Schwann and satellite cells of cranial nerve ganglions. To study the fate of MCMV in nerve tissue, we explanted trigeminal ganglions from newborn, suckling, and weanling mice, 3 to 36 days after intracranial inoculation. Negative explants were co-cultivated with mouse embryo tissue culture (METC) to test for latency. MCMV, identified by electron microscopy, replicated in fibroblasts, Schwann cells, and/or satellite cells and neurons of trigeminal explants from newborn and suckling, but not weanling, mice. No latent virus was detected by our methods. The age differences in viral replication may be due to the age-dependent intrinsic cellular mechanisms and host inflammatory and immunologic response. Though neurons are infected, they remain relatively resistant to CMV replication.